We are using the high sensitivity of the W-band spectrometer to measure the reduction rates of TEMPOL by small numbers (10-30) of cells. Cells (BHK, 106/ml) are placed in a 0.1 mm ID quartz tube and placed in the cavity of the W-band spectrometer. Temperature is controlled at 37oC. Signal-to-noise of the 10 fm TEMPOL sample is excellent. Experiments to measure reduction rates are underway.